NOVICE TO NINJA userHasRole($role) function confusion

Apologies if this topic has already been answered, but a quick search yielded no solution.

Ref: Novice to Ninja
File: chapter9/includes/ (pg.302)
Function: userHasRole($role)

Can someone please explain to me where the value for the argument ($role) comes from in this function.
I thought values needed to be passed into functions via arguments included in the function call.
I can’t see where $role has been declared or even a value for it.

Thanks in advance


If you scroll down to page 305, you will find this:

if (!userHasRole('Account Administrator'))
  $error = 'Only Account Administrators may access this page.';
  include '../accessdenied.html.php';

There you can clearly see, it will be passed a value. In this particular use, the $role used in userHasRole will contain ‘Account Administrator’

Thank You cpradio. Much appreciated. I was only looking in the access.php file.
Enjoy your day.